High molecular weight polymers and copolymers of 3-hydroxyoxetane and derivatives thereof

Abstract

High molecular weight (Mw>25,000, preferably >50,000; ninh up to 3) linear atactic poly (3-hydroxyoxetane) (PHO) are made by polymerizing the trimethylsilyl ether of 3-hydroxyoxetane with a coordination catalyst, or preferably with a cationic catalyst such as i-Bu3Al-0.7 H2O, followed by hydrolysis. The new polymer is atactic, highly crystalline, has a melting point of 155 DEG C., is devoid of measurable end groups, has a two-peak 13C-NMR, and can be readily compression molded at 200 DEG C. to a film which can be drawn at room temperature to give enhanced strength. Isotactic high molecular weight PHO (mp=223 DEG C.; DELTA Hf=25.6 cal/g) and branched high molecular weight PHO are also prepared.

Accordingly, what is claimed is: 
     
       1. The process of preparing high molecular weight branched poly(3-hydroxyoxetane) polymer comprising introducing into a sealed reactor vessel containing an inert atmosphere, a dry linear poly(3-hydroxyoxetane) having an inherent viscosity (0.1% in water at 30° C.) greater than 0.5, adding to said vessel a solvent and dispersion of NaH in an inert carrier; stirring the mixture until the poly(3-hydroxyoxetane) is thoroughly mixed therewith, adding glycidol to the stirred mixture and continue stirring until the reaction is complete and the branched polymer is formed; dialyzing said branched polymer to remove water solubles therefrom, and collecting the branched polymer. 
     
     
       2. High molecular weight branched poly(3-hydroxyoxetane) having a crystalline microstructure and a weight average molecular weight greater than 25,000.